The organs of all living things, including humans, gradually decline with age following birth and growth, and death occurs when their function stops and portions in which function has stopped exceed a certain degree. This process by which organ function gradually declines is referred to as aging. The skin is subjected directly to the effects of the surrounding environment, and although its function rarely stops completely since it has an important function in maintaining the conditions within the body, it is an organ likely to remarkably show signs of aging such as wrinkles, spots, darkening and sagging, which are particularly prominent at sites exposed to sunlight.
As aging of the skin progresses, the skin's defensive abilities against stimulation by oxidative stress and so forth diminish, and this causes a disturbance of the conditions inside the skin, which in turn further accelerates aging. Since sites exposed to sunlight in particular are continuously exposed to intense oxidative stress caused by irradiation with ultraviolet rays and so forth, the progression of aging is prominent. This progressive change in the skin is referred to as photo-aging, and in skin suffering from photo-aging, collagen, which is a constituting component that accounts for the majority of the dermis, decreases, thereby resulting in an aesthetically undesirable state such as deep, large wrinkles in the surface of the skin.
Although retinoic acid is used as a prescription drug in the US as a substance having ameliorative effects on wrinkles formed as a result of the progression of photo-aging, since it has problems in terms of safety to the occurrence of significant adverse side effects, it has not been approved for use in Japan. In addition, although substances including retinol (vitamin A), which is said to demonstrate effects as a result of being converted to retinoic acid after being absorbed into the body, ascorbic acid (vitamin C), which has antioxidative and collagen synthesis promoting effects, and tocopherol (vitamin E), which has potent antioxidative effects, have also been proposed for use as antiwrinkle agents, these have the shortcoming of being unable to produce sufficiently satisfactory effects. Thus, there has previously not been a substance for use as an antiwrinkle agent capable of demonstrating sufficiently satisfactory effects while also being safe to use.
In addition, many conventional antiwrinkle agents are chemically synthesized, and have numerous problems in terms of safety. On the other hand, with respect to naturally-occurring substances which have few problems in terms of safety, there are hardly any such substances known which can be used as antiwrinkle agents other than vitamins, and what is more, none of them have been obtained which adequately demonstrate ameliorative effects. Moreover, most of natural antiwrinkle agents such as retinol significantly lack photostability, and even if such antiwrinkle agents are effective, nearly all are difficult to formulate into preparations since they are rapidly decomposed in the preparations.
On the other hand, body fat is formed as a result of an excess of ingested energy relative to consumed energy being accumulated in the form of fat in white adipose tissue present around organs and beneath the skin. What is called obesity, in which body fat has accumulated in excess, is not only aesthetically undesirable, but also causes various diseases such as arteriosclerosis, thus making it undesirable in terms of health as well. Recently, there has been an increase in the incidence of obesity caused by such factors as overeating, lack of exercise and stress, and the reduction of body fat or prevention of accumulation thereof is becoming an important issue. In women in particular, there is growing trend towards a preference for a slim, trim physique in terms of appearance.
Capsaicins, which are contained in red peppers and so forth, for example, are known to be substances having obesity preventive action by binding with albumin in the blood and promoting the secretion of hormones from the adrenal glands that promote energy metabolism to activate lipolysis in the liver and adipocytes (see Non-patent document 1). However, since capsaicins exhibit potent stimulation, they have had the problems of limitations on their applications and amounts used.
The present inventors found that raspberry ketone, zingerone and derivatives thereof are effective in inhibiting obesity or improving an obese constitution by promoting the degradation of fat accumulated in adipose tissue (see Patent document 1). However, since raspberry ketone and zingerone have distinctive aroma, they were not necessarily satisfactory with respect to formulated amount and universality.
On the other hand, Guinea ginger (Aframomum melegueta), which is a plant of the Zingiberaceae family, is native to tropical regions mainly located in western Africa, and is used as a spice under the name “maniguette” or “grain of paradise”. Although Guinea ginger is used as a food seasoning or flavoring, studies have not been conducted on antiwrinkle agents or external compositions for skin using an extract thereof.
Paradol [1-(4′-hydroxy-3′-methoxyphenyl)-3-decanone] has been reported to be a component contained in a specific fraction of a seed extract of the aforementioned guinea ginger, and is a known substance represented by the following chemical formula (see Patent document 2).
Although paradol is proposed for use as a termiticide together with other analogs in the Patent document 2, there is no description of wrinkle ameliorative effects, lipolysis promoting effects or slimming effects, and there have been no studies conducted thus far on these effects.
Gingerol and shogaol present in ginger extracts have been proposed for use as active ingredients of promoters of horny layer restoration (see Patent document 3). However, since the paradol in the present invention is a component contained in specific plants of the Zingiberaceae family, and is hardly contained in ordinary ginger, it has not been proposed as an active component of ordinary ginger.
In consideration of the aforementioned circumstances, there has been a need for the development of an antiwrinkle agent and external composition for skin having superior ameliorative effects on wrinkles prominently actualized due to aging, and particularly at sites exposed to sunlight, superior effects in maintaining aesthetically healthy skin, as well as superior safety and stability. In addition, there has also been a need for the development of a lipolysis promoter having effective lipolysis promoting effects while allowing the formulated amount and application to be set as desired without pungent flavor or distinctive aroma, and an external composition for skin and food and beverage composition having superior lipolysis effects while also being superior in terms of characteristics of likeability such as flavor and aroma.    Patent document 1: (Japanese Unexamined Patent Publication No. 2000-169325)    Patent document 2: (Japanese Unexamined Patent Publication No. H10-152404)    Patent document 3: (Japanese Patent No. 3164455)    Non-patent document 1: Iwai, K. and Nakatani, N., ed.: Food Functions of Spice Components, 97, 1989).
As a result of conducting extensive studies in consideration of the aforementioned circumstances, the inventors of the present invention found that guinea ginger (Aframomum melegueta), which is a plant of the Zingiberaceae family, and particularly an extract obtained from the seeds thereof as well as an acylation treatment product thereof, along with paradol, which is a component contained in said extract, or an acylation derivative thereof, demonstrate superior ameliorative effects on wrinkles formed with aging, and particularly at sites exposed to sunlight, are effective in maintaining the skin in a dermatologically and aesthetically healthy state, are superior in terms of safety and stability, and are effective in inhibiting or preventing obesity by improving an obese constitution or preventing increases in adipose tissue as a result of promoting reduction of systemic or local adipose tissue, while also being superior materials capable of suppressing pungency and aromas that impair likeability, thereby leading to completion of the present invention.